<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        div{
            /*border-style: dotted;*/
            /*border-color: red;*/
            /*border-width: 10px;*/
            border: 2px solid blue;
            /*border-left:10px solid yellow ;*/
            /*border-right:10px dashed red ;*/
            border-radius: 50%;  /* 设置圆角 */
            width: 200px;
            height: 200px;
        }

    </style>
</head>
<body>

<div></div>
</body>
</html>